Balloon deliver apparatuses, or angioplasty balloons, are useful for treating maladies in patients that involve the patients' vasculature. For example, angioplasty balloon dilation is sometimes used for the treatment of stenosis, wherein a small balloon is disposed at the location of the stenosis and inflated to expand the stenosis in a vessel lumen and improve the vessel's patency. Angioplasty balloons are also useful for deploying stents in a patient's vasculature that maintain the vessel's locally expanded state or patency and prevent restenosis. It is noted that coronary stenting is believed to reduce restenosis rates in patients when compared with conventional balloon dilation. Amer. J. Cardio. 2002, 90, 1187-1192.
In either balloon angioplasty or stenting procedures, angioplasty balloons are typically used to expand a stenosis in a patient's vasculature. In procedures including the deployment of a stent, the angioplasty balloon may also expand and deploy the stent within the patient's vasculature. These procedures are traditionally preceded by the placement of a guidewire through the stenosis, which is followed by angioplasty balloon dilation at the stenosis with a balloon angioplasty catheter that has been advanced over the guidewire. The balloon angioplasty catheter is then withdrawn from the patient and a stent delivery system that includes the stent is advanced over the guidewire, and the stent is then deployed at the site of the dilated stenosis.
Conventional stenting procedures include the following steps:
1. Place coronary guidewire into wire introducer;
2. Load guidewire into guiding catheter;
3. Advance guidewire across lesion;
4. Remove wire introducer;
5. Load predilatation balloon angioplasty catheter onto guidewire;
6. Advance balloon catheter into guiding catheter;
7. Cross lesion with predilatation balloon;
8. Dilate lesion with balloon;
9. Angiography;
10. Remove predilatation balloon catheter;
11. Load stent delivery system (SDS) onto guidewire;
12. Advance SDS into guiding catheter;
13. Cross lesion with SDS;
14. Deploy stent at high pressure;
15. Angiography; and
16. Remove delivery system.
Because of the complexity of the procedure, conventional stenting often involves lengthy procedural times, prolonged exposure to radiation, lengthy administration of contrast agents, and great expense. J. Amer. Col. Cardio. 1999, 34, 1910-1915. Furthermore, the balloon predilation followed by stent placement often leads to major vascular trauma in a patient.